想在mysql里把一段用固定符号分隔的字符串，按分隔符分别列出来。就是一个典型的split应用，但是mysql却没有自带这个函数，在网上搜了一把。可以通过自建函数来解决，以下的函数来自互联网。
-
DELIMITER $$ -
CREATE FUNCTION `func_get_split_string_total`( -
f_string varchar(1000),f_delimiter varchar(5) -
) RETURNS int(11) -
BEGIN -
return 1+(length(f_string) - length(replace(f_string,f_delimiter,''))); -
END$$ -
DELIMITER ; -
-
-
DELIMITER $$ -
CREATE FUNCTION `func_get_split_string`( -
f_string varchar(1000),f_delimiter varchar(5),f_order int) RETURNS varchar(255) CHARSET utf8 -
BEGIN -
declare result varchar(255) default ''; -
set result = reverse(substring_index(reverse(substring_index(f_string,f_delimiter,f_order)),f_delimiter,1)); -
return result; -
END$$ -
DELIMITER ;
需要设置下参数：
SET GLOBAL log_bin_trust_function_creators = 1;下面我们来测试下：
-
CREATE TABLE "t" ( -
-> "t1" varchar(100) DEFAULT NULL, -
-> "t2" int(11) DEFAULT NULL -
-> ) ENGINE=MyISAM DEFAULT CHARSET=utf8; -
-
mysql> insert into t(t1,t2) values('a,b,c,d',1); -
Query OK, 1 row affected (0.00 sec) -
-
mysql> insert into t(t1,t2) values('a b c d',2); -
Query OK, 1 row affected (0.00 sec) -
-
mysql> select * from t; -
+---------+------+ -
| t1 | t2 | -
+---------+------+ -
| a,b,c,d | 1 | -
| a b c d | 2 | -
+---------+------+ -
2 rows in set (0.00 sec)
首先用func_get_split_string_total函数得到符合匹配的数量
-
mysql> select func_get_split_string_total(t1,',') from t where t2=1; -
+-------------------------------------+ -
| func_get_split_string_total(t1,',') | -
+-------------------------------------+ -
| 4 | -
+-------------------------------------+ -
1 row in set (0.00 sec)
然后用func_get_split_string得出你想要的字符串
-
mysql> select func_get_split_string(t1,',',1) from t where t2=1; -
+---------------------------------+ -
| func_get_split_string(t1,',',1) | -
+---------------------------------+ -
| a | -
+---------------------------------+ -
1 row in set (0.00 sec) -
-
mysql> select func_get_split_string(t1,',',2) from t where t2=1; -
+---------------------------------+ -
| func_get_split_string(t1,',',2) | -
+---------------------------------+ -
| b | -
+---------------------------------+ -
1 row in set (0.00 sec) -
-
mysql> select func_get_split_string(t1,',',3) from t where t2=1; -
+---------------------------------+ -
| func_get_split_string(t1,',',3) | -
+---------------------------------+ -
| c | -
+---------------------------------+ -
1 row in set (0.00 sec) -
-
mysql> select func_get_split_string(t1,',',4) from t where t2=1; -
+---------------------------------+ -
| func_get_split_string(t1,',',4) | -
+---------------------------------+ -
| d | -
+---------------------------------+ -
1 row in set (0.00 sec)
当然，这只是个思路，如果你想把所有字符串都列出来，可以写个过程，在里面循环一下。
希望能对这位朋友有帮助。
